new bridge . the original structure , dating to 1918 , is a 55 @ - @ foot @ - @ long ( 17 m ) span ##dre ##l arch span that was built by the ms ##hd as trunk line bridge no . 191 . the structure was listed on the nrhp on december 9 , 1999 , for its architectural and engineering significance . in december 2012 , the national park service approved the listing of the upper twin falls bridge that crosses the men ##omi ##nee river northwest of iron mountain . the structure is a single @ - @ span , pin @ - @ connected , camel ##back , through @ - @ truss bridge , and it is the only known example
new bridge. the original structure, dating to 1918, is a 55 @ - @ foot @ - @ long ( 17 m ) spandrel arch span that was built by the mshd as trunk line bridge no. 191. the structure was listed on the nrhp on december 9, 1999, for its architectural and engineering significance. in december 2012, the national park service approved the listing of the upper twin falls bridge that crosses the menominee river northwest of iron mountain. the structure is a single @ - @ span, pin @ - @ connected, camelback, through @ - @ truss bridge, and it is the only known example